Cap for a container

ABSTRACT

A cap (1) for a container having a screw threaded opening comprising an inner part (3) in the form of a screw threaded cap, an outer part (2) the inner part (3) being axially displaceable relative to the outer part (2) and biased therefrom between an unlocking and locking position, resilient biasing means (17) between the inner and outer parts, a boss (6), and engagement means (15) adapted to engage with the boss upon (6) depression of the outer part (2), such that turning the cap will unscrew it from the container wherein one of the boss (6) or engagement means (15) is located on the top surface of the inner part (3) and the other is located on the inner top surface of the outer part (2).

This invention relates to a cap for a container, particularly apharmaceutical container.

BACKGROUND OF THE INVENTION

British patent no. 2167050 relates to a two part child resistantpharmaceutical bottle cap which includes a hexagonal boss on the uppersurface of the inner part which on depression of the outer part, locksinto a hexagonal aperature in the top of the outer part. Twisting of theouter part in this locked position then releases the cap from thebottle. In the unlocked (child safety) position, however, there is aslight overlap between the uppermost edge of the boss and the innermostedge of the wall of the aperture, so that rotation of the outer partwears and rounds the corners of the boss eventually making it moredifficult to lock with the aperture and thus release the cap.

In addition, some medicines are viscous which can result in the innerpart becoming firmly stuck to the container. This leads to additionalforce being required to open the container which can speed up thewearing process.

SUMMARY OF THE INVENTION

Thus, the present invention provides a cap for a container having ascrew threaded opening comprising an inner part in the form of a screwthreaded cap, an outer part, the inner part being axially displaceablerelative to the outer part and biased therefrom between an unlocking andlocking position, resilient biasing means between the inner and outerparts, a boss, and engagement means adapted to engage with the boss upondepression of the outer part, a plurality of projections and a secondengagement means adapted to engage with said plurality of projectionsupon depression of the outer part, such that turning the cap willunscrew it from the container, wherein one of the boss or engagementmeans is located on the top surface of the inner part and the other islocated on the inner top surface of the outer part, and wherein one ofthe plurality of projections or second engagement means is located onthe top surface of the inner part and the other is located on the innertop surface of the outer part.

In a preferred embodiment of the invention the boss is hexagonal and islocated on the inner part and the engagement means consists of aplurality of spaced corner pieces located on the outer part.

Preferably the plurality of projections is located on the inner part andthe second engagement means is located on the outer part.

In a particularly preferred embodiment the second engagement meansconsists of a plurality of dogs associated with the resilient biasingmeans.

In a third preferred embodiment the outer part of the cap has asubstantially central aperture covered by a tamper evident coverconnected to the outer part by a hinge portion and at least onefrangible portion, and the boss carries a spigot which upon depressionof the outer part projects through the aperture with sufficient force tobreak the least one frangible portions.

In another aspect the present invention provides a cap for a containerhaving a screw threaded opening comprising an inner part, in the form ofa screw threaded cap, an outer part, the inner part being axiallydisplaceable relative to the outer part and biased therefrom between anunlocking and locking position, resilient biasing means between theinner and outer parts, a boss located on the inner part, a plurality ofprojections and engagement means adapted to engage with the projectionsupon depression of the outer part, wherein the outer part has asubstantially central aperture into which the boss is received upondepression of the outer part, such that the boss engages with theaperture on unscrewing the cap.

In a preferred embodiment of this aspect of the invention the boss ishexagonal and the plurality of projections are located on the inner partand the engagement means on the outer part.

Preferably the engagement means consists of a plurality of dogsassociated with the biasing means.

In a further preferred embodiment the aperture is covered by a tamperevident cover connected to the outer part by a hinge portion and atleast one frangible portion, such that upon depression of the outer partthe at least one frangible portion is ruptured by the boss received inthe aperture.

In addition, it has been found that coating at least one of the outer orinner parts with silicone can aid the effectiveness of the invention.Preferably the inner part is substantially coated with silicone. Thiscoating reduces torque allowing the biasing means to be made of thickerand/or stronger material. It may also aid in reducing "gumming up" ofthe cap by viscous liquids. Finally it also reduces the chance that theouter part can be pinched hard against the inner part resulting inengagement and opening.

The container cap of the present invention are preferably made ofplastics material.

In another aspect the invention relates to containers equipped with acontainer cap of the invention, preferably pharmaceutical containers.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example only withreference to the accompanying drawings in which:

FIG. 1 is a cross-sectional view of a cap of the invention in itsunlocked position (right-hand side) and locked position (left-handside);

FIG. 2 is an underneath plan view of the outer par: of the cap of FIG. 1showing parts of the internal mechanism thereof;

FIG. 3 is further cross-sectional axial view of the cap in the lockedposition;

FIG. 4 is a plan view of cap of FIG. 1 but not showing any internalmechanism;

FIG. 5 is a cross-sectional view of another embodiment of the invention;

FIG. 6 shows the outer part of the cap of FIG. 5, in underneath planview;

FIG. 7 is a cross-sectional view of another cap of the invention;

FIG. 8 shows the outer part of the cap of FIG. 7 in underneath planview.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In FIG. 1 it can be seen that the cap comprises a hollow inner part 1receivable within an outer (shell), part 2 in a snap fit manner. Theinner part 1 comprises a planar circular top 3 with a depending annularskirt 4 having an inner screw thread 5. A central hexagonal boss 6extends upwardly from the top 3 of the inner part 1 and a plurality ofspaced studs 7 are arranged therearound adjacent respective corners ofthe hexagonal boss 6. A spigot 8 projects from boss 6 and a linear wad 9is located against: the lower surface of the top 3 of the inner part 1.

The outer part 2 also comprises a planar circular top 10a with adepending circular skirt 10b having a circular bead 11 around its lowerinner edge, over which the lower edge of the inner piece snap fits. Asmall central aperture 12 is provided on the top of the outer part 10and is covered by a tamper evident cover piece 13 held in place atdiametrically opposed positions by a hinge 14a and a frangible web 14b.On depressing the outer part 2 for the first time the spigot 8 projectsinto the aperature 12 with sufficient force to rupture the frangibleportion 14b, thus providing tamper evidence.

Spaced outwardly from the central aperture 12 and extending downwardlyfrom, and formed integrally with, the inner surface of the top 10 of theouter part 2 are a plurality of corner pieces 15 conforming in outlineto the hexagonal boss 6 in a formation of three diametrically opposedpairs. Each corner piece 15 is formed from two limbs of a wall angled atabout 120° to neatly receive the corresponding corner of the hexagonalboss 6. In depth each corner-piece 15 is about the same, or about twicethe thickness of the top wall of the outer piece 2, and the spacing isabout half the length of a limb (although this is not critical and itcan be e.g. a third, three-quarters of a length spacing). In thisembodiment, there is an overlap between the upper edge of the boss 6 andthe lower edge of the corner-pieces 15.

Six resilient tongues 17 forming biasing means also depend at an anglefrom the inner surface of the top of the outer part 2 and are seriallyarranged in a circular fashion between the corner-pieces 15 and theskirt 10b. Extending downwardly adjacent the root of each tongue 17, isa corresponding abutment or dog 18.

In operation when the outer part 2 is rotated clockwise, the free endsof the tongues 17 abut the respective studs 7 on the top of the innerpart 3 to screw it and the whole cap onto the bottle. If, however, theouter part 2 is turned in a counter clockwise direction without alsopressing down, the outer part will turn freely relative to the innermember 3 with the free ends of the tongues 17 riding over the tops ofthe studs 7 of the inner part 2.

Furthermore on counter-rotation, even though there is a slight overlapbetween the inner edges of the corner-pieces 15 and the boss 6, the wearon the corners of the boss 6 is considerably reduced as a result thegaps between the corner-pieces 15 (that is the area of contact whichpreviously wore the corners, has been reduced).

On depression of the outer part 2 the corners of the boss 6 are receivedneatly into the corner-pieces 15 in a gripping fashion so that the topof the boss 6 lies adjacent or abuts the inner surface of the top 10 ofthe outer part 2 and the spigot 8 abuts against the tamper evident coverpiece 13 breaking the frangible connecting web 14b and hinging open thecover piece 13 (as shown in the left handside of FIG. 1). In thisposition the abutments or dogs of the outer part 2 are locked behind thestuds 7 of the inner part 1 to release/unscrew the cap from the bottleon clockwise rotation. If, however, this first opening mechanism fails(e.g. due to gumming up of the studs by a pharmaceutical substance),then the boss 6 which is now locked into the corner-pieces 15 will stillbe available (as a second opening mechanism) for releasing the cap 1.

In FIG. 2 the relationship between the spaced corner pieces 15 aroundthe aperature 12 can be more clearly seen. The gaps between the cornerpieces 15 greatly reduce wear on the boss received therein. Also thearrangement of the biasing tongues 17 and the abutments or dogs 18 isshown. Thus, the two separate engagement mechanisms and theirrelationship is portrayed.

FIG. 3 simply shows the cap of FIG. 1 in the unlocked position, i.e.before depression of the outer cap 2.

FIG. 4 shows the exterior upper surface of the cap 1 before thecontainer has been opened for the first time. Thus, the frangibleportion 14b is intact and the tamper evident cover 13 is still in place.

In FIG. 5 another embodiment of the invention is shown. Once again ahollow inner part 101 is received within an outer (shell) part 102 in asnap fit manner. The inner part 101 comprises a planar circular top 103with a depending annular skirt 104 having an inner screw thread 105. Acentral hexagonal boss 106 extends upwardly from the top 103 of theinner part 101 and a plurality of spaced studs 107 are arrangedtherearound adjacent respective corners of the hexagonal boss 106. Alinear wad 109 is located against the lower surface of the top 103 ofthe inner part 101.

The outer par: 102 also comprises a planar circular top 110a with adepending circular skirt 110b having a circular bead 111 around itslower inner edge, over which the lower edge of the inner piece snapfits. A hexagonal aperture 112 is provided on the top of the outer part102 and is covered by a tamper evident cover piece 113 held in place atdiametrically opposed positions by a hinge 114a and a frangible web114b.

Six resilient tongues 117 forming biasing means depend at an angle fromthe inner surface of the top of the outer part 102 and are seriallyarranged in a circular fashion. Extending downwardly adjacent the rootof each tongue 117, is a corresponding abutment or dog 118.

In operation when the outer part 102 is rotated clockwise, the free endsof the tongues 117 about the respective studs 107 on the top of theinner part 103 to screw it and the whole cap onto the bottle. If,however, the outer part 102 is turned in a counter clockwise directionwithout also pressing down, the outer part will turn freely relative tothe inner member 103 with the free ends of the tongues 117 riding overthe tops of the studs 107 of the inner part 102.

On depression of the outer part 102 the boss 106 is received in theaperture 112 such that the boss 106 abuts the sides of the aperture 112,and against the tamper evident cover piece 113 breaking the frangibleconnecting web 114b and hinging open the cover piece 113. In thisposition the abutments or dogs 118 of the outer part 102 are lockedbehind the studs 107 of the inner part 102 to release/unscrew the capfrom the bottle on clockwise rotation. In this cap the locking of theboss 106 into he aperture 112 and the studs/abutments opening meansprovide back up to each other for opening the cap.

In FIG. 6 it can be seen that in this embodiment the arrangement of theresilient tongues 117 and abutments/dogs 118 is essentially the same asfor the outer par: of the cap shown in FIG. 1. Here however instead ofcorner pieces there is provided a hexagonal aperture 112 adapted toreceive the boss 106.

FIGS. 7 and 8 show a further embodiment of the invention in which thereis no tamper evident cover provided. In this embodiment the inner part202 is provided with a boss 206 which is received within a plurality ofspaced corner pieces 215 located on the under surface of the outer part202. Similarly resilient tongues 217 depend downwards from the outerpart 202 and have abutments/dogs 218 associated with them which lockbehind studs 207 located on the inner piece 203. This cap operates inthe same way as the cap shown in FIG. 1 except that no tamper evidenceis provided.

It will be appreciated that other shapes of boss could be used, such asfor example a square or a triangle, although a hexagonal boss 6 is apreferred embodiment because it has more gripping points/corners.Furthermore there does not have to be a corresponding number ofcorner-pieces as corners as long as they are strategically positioned tosufficiently grip and rotate the inner part without putting too muchstress on the corner-pieces (i.e. to damage them). In the case of asymmetrical shaped boss such as a square or hexagon, preferably eachcorner-piece 215 is substantially opposite another corner-piece 215.Thus for a hexagonal boss 206 although an opposed pair of corner-pieces215 may be used preferably there are two opposed pairs, most preferablythree opposed pairs.

I claim:
 1. A two piece cap for a container having a screw threadedopening comprising:an inner part in the form of a screw threaded caphaving a top surface; an outer part having an inner top surface, theinner part being axially displaceable relative to the outer part andbiased therefrom between an unlocking and locking position; resilientbiasing means between the inner and outer parts; a boss; firstengagement means engageable with the boss upon depression of the outerpart, and a plurality of projections and a second engagement meansengageable with said plurality of projections upon depression of theouter part, such that turning the cap will unscrew it from thecontainer; wherein one of the boss or first engagement means is locatedon the top surface of the inner part and the other is located on theinner top surface of the outer part; and wherein one of the plurality ofprojections or second engagement means is located on the top surface ofthe inner part and the other is located on the inner top surface of theouter part.
 2. The cap as claimed in claim 1 where the boss is locatedon and extends upwardly from the top surface of the inner part and thefirst engagement means is located on and extends downwardly from theinner top surface of the outer part.
 3. The cap as claimed in claim 2wherein the boss is hexagonal and there are two or three pairs ofsubstantially opposed corner pieces, for receiving and engaging with thehexagonal boss.
 4. The cap as claimed in claim 1 wherein the outer parthas a substantially central aperture covered by a tamper evident coverconnected to the outer part by a hinge portion and at least onefrangible portion, and the boss carries a spigot which upon thedepression of the outer part projects through said aperture withsufficient force to break at least one frangible portion.
 5. The cap asclaimed in claim 1 wherein the boss is hexagonal and there are two orthree pairs of substantially opposed corner pieces for receiving andengaging with the hexagonal boss.
 6. The cap as claimed in claim 5wherein each corner piece is formed from two limbs of a wall angled atabout 120° to neatly receive the corresponding corner of the hexagonalboss.
 7. The cap as claimed in claim 6 wherein in depth each cornerpiece is about the same or about twice the thickness of the top wall ofthe outer part.
 8. The cap as claimed in claim 1 wherein the pluralityof projections is located on the inner part and the second engagementmeans is located on the outer part.
 9. The cap as claimed in claim 8wherein the second engagement means consists of a plurality of dogsassociated with resilient biasing means, and the dogs lock with theprojections on depression of the outer part.
 10. The cap as claimed inclaim 1 wherein at least one of an outer surface of the inner part andan inner surface of the outer part is substantially coated withsilicone.
 11. The cap as claimed in claim 10 wherein the outer surfaceof the inner part is substantially coated with silicone.
 12. The cap asclaimed in claim 1 which is made of plastics material.
 13. A containerhaving a screw threaded opening, wherein the container is equipped witha cap as claimed in claim 1, such that the screw threads of thecontainer engage the threads on the inner part of the cap.
 14. Thecontainer as claimed in claim 13 which is a pharmaceutical container.15. A two piece cap for a container having a screw threaded openingcomprising:an inner part in the form of a screw threaded cap having atop surface; an outer part having an inner top surface, the inner partbeing axially displaceable relative to the outer part and biasedtherefrom between an unlocking and locking position; resilient biasingmeans between the inner and outer parts; a boss extending upwardly fromthe top surface of the inner part; a plurality of spaced corner piecesextending downwardly from the inner top surface of the outer part, saidcorner pieces conforming in outline and engageable with the boss upondepression of the outer part; a plurality of projections; and a secondengagement for engaging with said plurality of projections upondepression of the outer part, wherein one of the plurality ofprojections or second engagement means is located on the top surface ofthe inner part and the other is located on the inner top surface of theouter part.
 16. The cap as claimed in claim 15 wherein the boss ishexagonal and the corner pieces are in three diametrically opposed pairsconforming in outline to the hexagonal boss.
 17. A two piece cap for acontainer having a screw threaded opening comprising:an inner part inthe form of a screw threaded cap having a top surface; an outer parthaving an inner top surface, the inner part being axially displaceablerelative to the outer part and biased therefrom between an unlocking andlocking position; resilient biasing means between the inner and outerparts; a boss; first engagement means engageable with the boss upondepression of the outer part; a plurality of projections and a secondengagement means engageable with said plurality of projections upondepression of the outer part, such that turning the cap will unscrew itfrom the container; wherein one of the boss or first engagement means islocated on the top surface of the inner part and the other is located onthe inner top surface of the outer part; wherein one of the plurality ofprojections or second engagement means is located on the top surface ofthe inner part and the other is located on the inner top surface of theouter part; and wherein the outer part has a substantially centralaperture covered by a tamper-evident cover and at least one frangibleportion, and the boss carries a spigot which upon depression of theouter part projects through said aperture with sufficient force to breakat least one frangible portion of the tamper-evident cover.